Isobutoxy-s-(4-chlorophenyl) ethylphosphonodithioate

ABSTRACT

ISOBUTOXY ETHYLPHOSPHONODITHIOATES OF THE FORMULA   R,R&#39;&#39;,(I-C4H9-O-P(=S)(-C2H5)-S-)BENZENE   WHEREIN R IS HYDROGEN OR METHYL AND R1 IS HYDROGEN OR CHLORINE. THE COMPOUNDS ARE USEFUL AS INSECTICIDES. REPRESENTATIVE COMPOUNDS ARE ISOBUTOXY-S-PHENYL ETHYLPHOSPHONODITHIOATE, ISOBUTOXY-S-(4-CHLOROPHENYL) ETHYLPHOSPHONODITHIOATE, ISOBUTOXY-S-(2-METHYL-5-CHLOROPHENYL) ETHYL PHOSPHONODITHIOATE, AND ISOBUTOXY-S-(P-TOLYL) ETHYLPHOSPHONODITHIOATE.

United States Patent 3,642,958 ISOBUTOXY-S-(4-CHLOROPHENYL)ETHYLPHOSPHONODITHIOATE Mervin E. Brokke, Richmond, Julius J. Menu,Saratoga,

and Stephen C. Dorman, Los Gatos, Calif., assignors to Staulfer ChemicalCompany, New York, N.Y. No Drawing. Filed May 14, 1968, Ser. No. 728,902Int. Cl. C07f 9/40; A01n 9/36 US. Cl. 260-961 1 Claim ABSTRACT OF THEDISCLOSURE Isobutoxy ethylphosphonodithioates of the formula wherein Ris hydrogen or methyl and R is hydrogen or chlorine. The compounds areuseful as insecticides. Representative compounds are isobutoxy-S-phenylethylphosphonodithioate, isobutoxy-S-(4-chlorophenyl)ethylphosphonodithioate, isobutoxy-S-(Z-methyl chlorophenyl) ethylphosphonodithioate, and isobutoxy-S- (p-tolyl)ethyl phosphonodithioate.

This invention relates to certain new isobutoxy ethylphosphonodithioatesand their utility as insecticides. The new compounds comprising thepresent invention have the general formula wherein R is hydrogen ormethyl and R is hydrogen or chlorine.

The phosphonic acid esters of this invention are prepared through thecondensation reaction involving an appropriate thiophenol and O-isobutylethanephosphonochloridothioate. The reaction is carried out in thepresence of a suitable solvent, such as acetone, methylethyl ketone,benzene, toluene, xylene and the like. The solvent can consist of two ormore of these solvents. The reaction is promoted by the addition to thereaction system of such organic bases as pyridine, triethylamine,dimethylaniline, or such alkali materials as sodium hydroxide andpotassium hydroxide. Normally, there is an initial exothermic reactionwhich requires cooling and after this period the reaction is taken tocompletion by heating.

The compounds of the present invention are prepared in accordance withthe following illustrative examples:

EXAMPLE 1 Preparation of isobutoxy S-(Z-methyl-S-chlorophenyl)ethylphosphonodithioate Triethylamine (20.2 g., 0.2 M) is added withstirring and cooling (below 30 C.) to a mixture of 2-methyl-5-chlorothiophenol (31.7 g., 0.2 M) and O-isobutylethanephosphonochloridothioate (40.1 g., 0.2 M) in 200 ml. benzene.There is an exothermic reaction and a white precipitate is formed. Afterthe addition, the mixture is heated under reflux for about one hour,cooled, poured into water and shaken. The organic layer is separated,combined with a benzene extract of the aqueous layer, washed with dilutepotassium hydroxide and water. The organic layer is dried over sodiumsulfate, filtered and the organic solvent removed. After distillation,there is obtained 51.2 g. of a liquid n =1.-5702, boiling point3,642,958 Patented Feb. 15, 1972 hoe 138 C. at 0.06 mm., 95.1 percentpurity by gas chromatography.

Elementary analysis.-Theory (percent): C, 48.36; H, 6.24; S, 19.86.Found (percent): C, 48.51; H, 6.04; S, 19.54. Infrared spectroscopyconfirmed the structure.

EXAMPLE 2 Preparation of isobutoxy S-phenyl ethylphosphonodithioate In asimilar manner as Example 1, 13.2 g. (0.12 M) of thiophenol, 20.0 g.(0.1 M) of O-isobutyl ethanephosphonochloridothioate and 12.1 g. (0.12M) triethylamine are reacted to yield 31.1 g. of crude material. Aftervacuum distillation B.P. 129 C. at 0.05 mm. there is obtained 19.2 g. ofthe title compound, n 1.5672.

Elementary analysis.Theory (percent): C, 52.53; H, 6.98; S, 23.37. Found(percent): C, 52.63; H, 6.70; S, 22.78. Infrared spectroscopy confirmedthe structure.

EXAMPLE 3 Preparation of isobutoxy S-(4-chlorophenyl)ethylphosphonodithioate Insecticidal evaluation tests The followinginsect species are subject to evaluation tests for insecticidalactivity.

(1) Housefiy (HF )Musca domestica (Linn) (2) German Roach (GR)-Blattellagermanica (Linn) (3) Salt-marsh caterpillar (SMC)Estigm*ene acrea(Drury) (4) Milkweed Bug (MWB)Onc0peltus fasciatus (Dallas) (5) LygusBug (LB)Lygus hesperus (Knight) Aliquots of the toxicants, dissolved inan appropriate solvent such as acetone, are diluted with watercontaining 0.002% of a wetting agent, Sponto 221 (a polyoxyether ofalkylated phenols blended with organic sulfonates). Test concentrationsrange from 0.1% downward to that at which 50% mortality is obtained. Inthe tests, utilizing these species, 10 one-month old nymphs of theGerman cockroach and lygus bug and two-week old nymphs of milkweed bugare placed in separate circular cardboard cages sealed on one end withcellophane and covered by a cloth netting on the other. Testconcentrations for the lygus bug range from 0.05% downward to that atwhich 50% mortality is obtained. Each of the aqueous suspensions of thecandidate compounds are sprayed onto the insects through the clothnetting by means of a hand spray gun. Percent mortality in each caserecorded after 72 hours, and the LD values expressed as percent oftoxicant in the aqueous spray was recorded.

For testing the salt marsh caterpillar, test solutions are prepared inan identical manner and at concentrations the same as for the Germancockroach and the milkweed bug above. Sections of bitter dock (Rumexobtusifolus) leaves, 1-1.5 inches in length are immersed in the testsolutions for 10 to 15 seconds and placed on a wire screen to dry. Thedried leaf is placed on a moistened piece of filter paper in a Petridish and infested with five third-instar larvae. Mortality of the larvaeis recorded after 72 hours and the LD values are expressed as percentactive ingredient in the aqueous suspension to effect approximately 50percent kill of the test insects.

The following procedure is used to test housefiies. A stock solutioncontaining 100 rag/ml. of the toxicant in an appropriate solvent such asacetone is prepared. Aliquots of this solution are combined with lmilliliter of an acetone-peanut oil solution in a glass Petri dish andallowed to dry. The aliquots are employed to achieve desired toxicantconcentrations ranging from 100 g. per Petri dish to that at which 50%mortality is attained. The Petri dishes are placed in a circularcardboard cage, closed on the bottom with cellophane and covered on topwith cloth netting. Twenty-five female housefiies 3 to 11 days old areintroduced into the cage and the percent mortality is recorded after 48hours. The LD values are expressed in terms of ,ug. per 25 female flies.

The results of these tests are given in the following Table I:

TABLE I.INSECTICIDAL EVALUATION TESTS [LDsu values] Percent HF ExampleNo. g/25 9) GR SMC MWB LB NOTE.A=O-ethyl S-(4-cl1loropl1enyl)ethylphosphonodlthioate.

TABLE II.MAMMALIAN TOXICITY: ACUTE ORAL LDsu, MALE RATS ReportedReported 95% confidence result Test; result Test limits Test CompoundNo. 1 N0. 2 No. 2

Example 3, mgJkg 79 58. 4 43. 0-79. 4 A, lug/kg 6 5. 84 4. 30-194 Thesame test procedure as mentioned above for saltmarsh caterpillar is usedfor cotton bollworm (Heliothis zea (Boddie) except that leaves ofRomaine lettuce were utilized as the host plant rather than bitter dock.The compound of Example 2 has an LD of 0.005% and the compound ofExample 3 has an LD of 0.003% against cotton bollworm.

The compounds are also active against black bean aphid (Aplzis fabae(Scop.)). Nasturtium plants (Tropaeolum sp.) approximately 2 to 3 inchestall are used as the host plant. The plants are infested with 50 to 75aphids of various ages. Twenty-four hours after infestation, they aresprayed to the point of run-ofi? with an aqueous suspension of thecandidate toxicant. Test concentrations range from 0.05% to that atwhich 50% mortality is obtained. The results obtained for the compoundsof Examples 1, 2 and 3 against black been aphid in this test are 0.003%,0.003% and 0.003 respectively.

Soil insecticide screening procedure.-In this test, the chemical isincorporated into a mixture of sand and vermiculite at a concentrationof 5 p.p.m. (parts per million) and placed in a quart jar. Followingthis step, twenty-five, five-day old housefly (Musca domestica) larvaeare introduced into the treated soil and allowed to remain in the sealedjar for 48 hours.

At the end of this time, the larvae are removed and placed on moistenedfilter paper in a Petri dish, at which time the number of motile larvaeand the number of pupae are counted. An immobile larva is considered tobe dead. The pupae are allowed to remain in the Petri dish until theadult flies have emerged. Mortality is determined by subtracting thenumber of emerged adult flies from twentyfive, which was the originalnumber of larvae placed into the soil.

If ninety or more percent mortality is obtained at the screeningconcentration, the compound is tested at lower rates until 50% mortalityis obtained. The results obtained in this test are: Example 1-3 p.p.m.,Example 2 1 p.p.m., and Example 3--l p.p.m.

In practice and to realize the desired activity, the insecticides of thepresent invention are advantageously applied to harmful insects in theform of compositions such as emulsions, suspensions, granules, solutionsor dusts. Insecticidal compositions of the present invention compriseessentially at least one active compound represented herein with asuitable carrier or solvent of the type commonly employed forinsecticidal agents. Examples of solid carriers are talc, chalk,bentonite, clay, corn grits, and the like. Examples of liquid carriersor solvents are water, xylene, alcohols, lower alcohols such as methanolor ethaol, ketones, such as acetone or methylethyl ketone, liquidpetroleum hydrocarbons and the like. The formulations may containwetting agents, dispersing agents and emulsifiers. They may also containother agricultural chemicals such as herbicides, fungicides, otherinsecticides, fertilizers, vermicides, and the like.

The concentration of a compound of the present invention, constitutingan effective amount in best mode of administration in the utilitydisclosed is readily determinable by those skilled in the art. Variouschanges and modifications are possible Without departing from the spiritand scope of the invention described herein and will be apparent tothose skilled in the art to which it pertains. It is accordinglyintended that the present invention shall only be limited by the scopeof the claim.

What is claimed is:

1. The compound isobutoxy S-(4-chlorophenyl) ethylphosphonodithioate.

References Cited UNITED STATES PATENTS 3,149,143 9/1964 Newallis et al.26096'l 3,305,610 2/1967 Szabo et al. 260-961 CHARLES B. PARKER, PrimaryExaminer A. H. SUTTO, Assistant Examiner US. Cl. X.R. 424222

